Flight History
The accident occurred on 22 June 2002 at approximately 13:30 local time. The helicopter, a Robinson R-22 Beta registered as EC-FEX, was operated by the pilot on a private VFR flight. It departed from a field in Mollerusa (Lleida) with only the pilot on board, intending to pick up a passenger at Benabarre airfield (Huesca), overfly the passenger's farms and the Canelles reservoir, then return to the origin. The flight plan and estimated times were communicated to Sabadell Airport.
The pilot reported that the initial departure occurred between 11:30 and 12:00 local time. The flight proceeded normally, including landing and takeoff at Benabarre, overflights of farms and the village of Estopiñán del Castillo, and finally the Canelles reservoir, initially at about 500 feet. While over the reservoir, the pilot began an approach to a peninsula near a dock but aborted upon seeing one or two people practicing scuba diving. He then decided to head toward the dam before returning to Benabarre.
Accident Sequence
According to the pilot, he saw electrical towers on both sides of the dam and the power lines between them. While gaining altitude to clear the lines, the helicopter "suddenly sank, losing altitude." In the new trajectory, fearing collision with the wires, the pilot lowered the collective and pulled back on the cyclic, with no further recollection of the flight.
A witness stated that other witnesses (who left the scene) reported that the helicopter was flying very low from inside the reservoir toward the dam, and just after crossing it, it began to spin and fell down the outer face of the dam into the spillway basin. The helicopter sank in the basin, which has a maximum depth of about 5 meters.
Injuries and Damage
The pilot managed to surface and climb onto a rock with serious injuries, and was rescued and evacuated by people who arrived almost immediately. The passenger remained submerged with the helicopter and was later recovered deceased. The helicopter sustained severe damage, rendering it practically unrecoverable for flight.
Investigation and Cause
The investigation concluded that the accident was caused by a decrease in main rotor RPM during the climb to clear the power lines near the dam. The pilot was unable to recover this rotor speed loss during the subsequent uncontrolled descent of the helicopter.